The forbidding black chair awaits its next nervous occupants as the demanding quiz returns for its 30th season.Tonight's quartet of contenders will be answering questions on a typically eclectic mix of specialist subjects - the history of US submarines, Anne McCaffrey's Dragonriders of Pern books, the Blackadder TV comedy series and the life and works of Ivor Novello. John Humphrys asks the questions and delivers the verdicts.